Problem: Subtract. $\dfrac{5}{2} - \dfrac{6}{8} = $
Solution: Before we can subtract our fractions, they need to have the same denominator. $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\frac{1}{8}$ $\dfrac{5}{2}$ $\dfrac{6}{8}$ $\dfrac{5}{2}-\dfrac{6}{8}$ Let's look at the multiples of each denominator and see which multiples they have in common. Denominator Multiples ${2}$ $2, {4}, 6, \underline{8}$ $8}$ $\underline{8}, 16, 24$ The least common denominator is ${8}$. Let's use multiplication to make each fraction have a denominator of $8$. ${\dfrac{5}{2}}=\dfrac{{5} \times 4}{{2} \times 4} = {\dfrac{20}{8}}$ Now, we can subtract ${\dfrac{20}{8}} - \dfrac{6}{8}}$. $\dfrac{20}{8}$ $\dfrac{6}{8}$ $\dfrac{20}{8} - \dfrac{6}{8}$ $=\dfrac{{20}-6}}{8}$ $=\dfrac{14}8$ ${\dfrac{5}{2}} - \dfrac{6}{8}} = \dfrac{14}{8}$ We can also write $\dfrac{14}{8}$ as $\dfrac74$ or $1\dfrac34$.